Many electrical devices that utilize a plug-in power source (e.g., household power connection) consume energy while switched off and not in use. This is primarily due to a transformer or power supply that remains connected to the power source even during periods of inactivity. One common method of powering these electrical devices includes a step-down transformer with a regulator. Common examples of such devices include mobile phone chargers, VCRs, televisions, stereos, computers, and kitchen appliances.
The devices that remain powered waste energy through their transformers and/or power supplies that remain connected to the power source. Such power loss is commonly referred to as a phantom power load because the power consumption does not serve a purpose. The electrical device or appliance is typically in a standby state or otherwise inactive when drawing current and is not serving a useful function. In aggregate, a large number of phantom loads contribute to a significant portion of essentially wasted power.
One method of preventing a phantom load is to physically unplug an appliance from the electrical outlet when it is not in use. This completely disconnects the appliance from the power source and eliminates phantom loading. However, the user then must manually plug in the load when load-use is desired and then unplug the load when use is no longer desired. Such ongoing plugging-in and unplugging may be a time consuming task as well as increase wear and tear on the electrical outlet, plug, and wiring to the load.
Consequently, there is a need to reduce the amount of power consumption from loads that are not in use to reduce energy waste. More generally, there is a need to selectively control a load based on the behavior of the load itself.